Private Stair Geometry Pre-check

How to use the Private Stair Geometry Pre-check

1. Confirm the fixed scope matches a straight private stair serving one dwelling in England.
2. Enter the total floor-to-floor height.
3. Specify the available going (horizontal run) distance.
4. Review the starting set-out, or enter a custom riser and going.
5. Compare the four geometry checks, then have the complete stair reviewed before material is cut.

Why use this tool

• Shows rise, going, 2R+G and pitch against the published private-stair geometry guidance.
• Makes the assumed straight-flight scope and excluded checks visible before the result.
• Provides a dimensioned starting profile for discussion with the stair designer and Building Control.

Approved Document K's current private-stair table for England gives a rise of 150–220mm, going of 220–300mm, a normal 2R+G relationship of 550–700mm and a maximum pitch of 42 degrees. Those four values are only part of a safe stair design. This pre-check does not assess headroom, landings, doors, handrails, guarding, openings, construction consistency, fire escape, accessibility, structure or site workmanship, so it cannot declare the whole stair compliant. Use it for an early straight-flight set-out and have the complete design reviewed before ordering or cutting materials.

Part of Builder Tools Calculators — construction tools for UK tradespeople.